AP EXAM REVIEW SESSION – MOLECULAR GENETICS
ASSESSMENT QUIZ
Use the following terms to answer questions 1-3.
A. telomere
B. DNA polymerase
C. helicase
D. primer
E. DNA ligase
1. Joins the sugar-phosphate backbones of the Okazaki fragments to make a complete DNA strand.
2. Catalyzes elongation of new DNA at replication fork.
3. Catalyzes the unwinding of double-stranded DNA prior to transcription.
Refer to the diagram below to answer question 4 and 5. The DNA samples were cut with one type of restriction enzyme and then, the
samples were separated by gel electrophoresis.
4. The differential migration speed of the different DNA fragments is due to
a. amount of radioactivity in the samples
b. degree to which the samples were negatively charged
c. degree to which the samples were positively charged
d. size of the fragments within the sample
e. polarity of the samples
5. Which of the following is a true statement?
a. The DNA strand of sample 2 was originally the longest.
b. The DNA strand of sample 4 was originally the shortest.
c. Samples 2 and 4 are the same DNA sample.
d. Sample 2 was cut at more restriction sites than was sample 4.
e. Sample 4 was cut at more restriction sites than was sample 2.
6. Once a plasmid has incorporated specific genes, such as the gene coding for ampicillin resistance, the plasmid may be
cloned by
a. inserting it into a virus to generate multiple copies
b. treating it with a restriction enzyme
c. inserting it into a suitable bacterium in order to produce multiple ones
d. running it on a gel electrophoresis
e. infecting it with a mutant cell in order to incorporate the gene of interest
7. The nucleotide sequence of a DNA molecule is 5’- C-A-T-3’. What is the nucleotide sequence of the tRNA anticodon?
a. 5’-G-T-A-3’
b. 5’-G-U-A-3’
c. 5’-C-A-U-3’
d. 5’-U-A-C-3’
e. 5’-G-U-G-3’
8. The working of the lac operon is important because it
a. represents how mammals use lactose
b. illustrates how RNA is processed after it is transcribed
c. illustrates possible control on the cell cycle and may lead to an understanding about the nature of a malignancy
d. is proof of semi-conservative replication of DNA
e. represents a principle means by which genes are regulated in prokaryotes
9. Which is directly responsible for the removal of introns during RNA processing in a eukaryotic nucleus?
a. GTP
b. the poly (A) tail
c. exons
d. the promoter
e. SNRPs
10. To which part of the DNA strand does RNA polymerase attach in the synthesis of proteins?
a. the primer
b. the operator
c. the promoter
d. the regulator
e. the cAMP binding site
Use the following terms to answer questions 11-12.
A. Transposon
B. Transformation
C. Transcription
D. Transduction
E. Translation
11. DNA from one strain of bacteria is taken up by another strain of bacteria
12. DNA is transferred using a viral vector
13. Polymerase chain reaction enables lab technicians to do which of the following very quickly?
a. isolate gene-source DNA
b. insert DNA into an appropriate vector
c. introduce the cloning vector into a host cell
d. amplify DNA samples
e. identify clones carrying the genes of interest
14. In the operon, the operator is the binding site for the
a. promoter
b. regulator
c. repressor
d. RNA polymerase
e. inducer
15. Referring to the diagrams below, choose the statement that best depicts the way in which DNA is replicated.
a. A depicts semi-conservative replication which was proved by Meselsohn and Stahl.
b. B depicts semi-conservative replication which was proved by Meselsohn and Stahl.
c. A depicts semi-conservative replication which was proved by Hershey and Chase.
d. A depicts semi-conservative replication which was proved by Griffith.
e. C depicts semi-conservative replication which was proved by Griffith.
16. The discontinuous strand during DNA replication is known as the
a. leading strand
b. lagging strand
c. promoter
d. operator
e. operon
17. Which of the following statements is true about the leading strand during DNA synthesis?
a. Primase reads the DNA and adds DNA in short segments.
b. DNA replication proceeds in the 3’→5’ direction when laying down RNA nucleotides.
c. The short segments of DNA are lengthened by DNA polymerase to form Okazaki fragments.
d. DNA polymerase reads the DNA and adds nucleotides to the leading strand continuously.
e. DNA polymerase unites separate Okazaki fragments on the leading strand.
18. Which statement below is true about telomeres and telomerase?
a. Telomerase prevents the shortening of chromosomes.
b. Telomerase is active throughout the lifetime of an individual.
c. Telomeres postpone the ends of chromosomes being eroded by replication.
d. Telomeres are specific genes which are not needed as an individual ages.
e. Telomeres are added in both the 3’→5’ and 5’→3’ direction by telomerase.
19. During translation,
a. the mRNA moves from the P site to the A site.
b. a large ribosomal subunit translates the start codon (AUG) and then the small subunit attaches.
c. a tRNA begins at the P site with a complimentary codon to the mRNA sequence.
d. each tRNA leaves the A site after transferring its amino acid to the mRNA.
e. the polypeptide is transferred and attached to the newly arriving amino acid in the A site.
20. If the percentage of adenine is 20% in a given sample of DNA, then what would be the percentage of guanine?
a. 20%
d. 80%
b. 30%
e. 60%
c. 40%
21. Which of the following is true about prokaryotic gene regulation?
a. A regulator gene codes for a repressor protein that controls the operon.
b. An operator is the sequence of DNA where RNA polymerase attaches.
c. Promoters code for enzymes and are transcribed as a unit.
d. A terminator determines when the operon becomes inactive.
e. Structural genes are located outside the operon and code for enzymes.
22. The enzyme that synthesizes cDNA is
a. primase
b. ligase
c. DNA polymerase
d. synthase
e. reverse transcriptase
23. The direction of migration in gel electrophoresis is due to
a. hydrogen bonds between molecules.
b. number of carbon molecules in the deoxyribose.
c. anti-parallel nature of DNA.
d. covalent bonds between the phosphates and nucleotides.
e. negative charge in the sugar – phosphate backbone.
24. A restriction map of a circular DNA plasmid is constructed based upon electrophoretic separation of the DNA. From
this map, which of the following statements could NOT be concluded?
a. The uncut DNA plasmid is 11.043 bp long.
b. Treatment with EcoRI and HpaI will result in fragments of 1807 and 9236 bp.
c. DNA cut with EcoRI will result in fragments of 4936 bp, 1807 bp, and 4300 bp.
d. Treatment with BgIII and EcoRI will result in fragments of 4936 bp and 6107 bp.
e. DNA cut with all three restriction enzymes will result in fragments of 4936 bp, 1807 bp, and 4300 bp.
25. What is the probability that individual aabbccDdEeff and AABbCCDdeeFF wll have a child heterozygous for each trait?
a. 1/64
b. 1/8
c. 1/4
d. 1/16
e. 3/16
Free Response
The flow of genetic information from DNA to protein in eukaryotic cells is called the central dogma of biology.
a) Explain the role of each of the following in protein synthesis in eukaryotic cells.
 RNA polymerase
 Spliceosomes (snRNPs)
 Codons
 Ribosomes
 tRNA
b) Cells regulate both protein synthesis and protein activity. Discuss TWO specific mechanisms of protein regulation
in eukaryotic cells.
c) The central dogma does not apply to some viruses. Select a specific virus or type of virus and explain how it
deviates from the central dogma.